Well jet device

ABSTRACT

The invention relates to pumping equipment. The inventive jet device comprises a packer, a pipe column and a cradle in which drain ports are embodied and on which a jet pump is mounted in a body. Said body is provided with a channel for supplying an active medium to the nozzle, a channel for supplying a pumped-out medium, and a channel for evacuating the mixture of said mediums. The body also comprises a through channel embodied therein above the channel for supplying a pumped-out medium, connected thereto and used for arranging a sealing unit. Said sealing unit comprises a channel for passing the pumped out medium of a cable and a channel for supplying the pumped out medium of the cable used for arranging instruments and equipment. The channel for supplying a pumped-out the active medium is connected to the drain ports and to the space around the pipe column by means of said ports. The channel for evacuating the mixture the mediums from the jet pump is connected to the internal space of tubes above the jet pump. The sealing unit is embodied in such a way that it makes it possible to arrange thereinside a mechanism for bringing in the well and extracting therefrom the body containing the jet pump. A threaded hole for connecting autonomous measuring instruments to the body is embodied in the lower part thereof.

FIELD OF INVENTION

[0001] This invention relates to the field of pumping engineering,mainly to downhole jet units for oil production.

PRIOR ART

[0002] Known in the art is a downhole jet unit comprising a jet pumpinstalled on the production string in the well and a geophysicalinstrument placed in the production string below the said jet pump (RU2059891 C1).

[0003] The said jet pumping unit enables to pump different extractedmedia, e.g., oil, out of the well with the simultaneous treatment of theextracted medium and the well formation zone, but the said unit providesfor supply of a working medium to the nozzle of the jet unit along thestring, which in some cases narrows the field of application of the saidunit.

[0004] The closest, as to its technical essence and the achievableresult, to this invention is a downhole jet unit comprising a packer, apiping string having a support wherein drain ports are made and ontowhich a jet pump with its housing is installed, the said housing of thesaid pump comprising a passage for supplying an active medium to thenozzle of the jet pump, a passage for supplying the medium, as pumpedout of the well, to the jet pump and a passage for removing a mediummixture from the jet pump, and in the housing, above the passage forsupplying a pumped out medium, a through passage in communication withthe latter being made with a mounting face for installing a sealingassembly, and the sealing assembly comprises a through passage with thepossibility of leading, through the latter and the said passage forsupplying the pumped out medium, a cable for the purpose of installing,in the well below the jet pump, instruments and equipment with thepossibility of moving them along the well bore when the jet pump is oris not operated (RU 2143597 C1).

[0005] The said downhole jet unit enables to perform various productionoperations in the well below the jet pump installation level by, interalia, reducing a pressure difference both above and below the sealingassembly. However, the said downhole jet unit does not enable to utilizeits possibilities in full due to non-optimal relationships betweendimensions of various components of the construction of the downhole jetunit and due to such arrangement of the jet pump in its housing that isnon-optimal for a number of applications.

DISCLOSURE OF INVENTION

[0006] The objective of this invention is to optimize the arrangementand the dimensions of various components of the construction of the welljet unit and, owing to it, to raise the reliability of operation of thewell jet unit.

[0007] The stated objective is achieved owing to the fact that the welljet unit comprises a packer, a piping string having a support whereindrain ports are made and onto which a jet pump with its housing isinstalled, the said housing of the said pump comprising a passage forsupplying an active medium to the nozzle of the jet pump, a passage forsupplying the medium, as pumped out of the well, to the jet pump and apassage for removing a media mixture from the jet pump, and in thehousing, above the passage for supplying a pumped out medium, a throughpassage in communication with the latter being made with a mounting facefor installing a sealing assembly, and the sealing assembly comprises athrough passage with the possibility of leading, through the latter andthe said passage for supplying the pumped out medium, a cable for thepurpose of installing, in the well below the jet pump, instruments andequipment with the possibility of moving them along the well bore whenthe jet pump is or is not operated, wherein, according to thisinvention, the passage for supplying the active medium to the nozzle ofthe jet pump communicates with the drain ports and through the latterwith the space surrounding the piping string, the passage for removing amedia mixture from the jet pump communicates with the inner cavity ofthe piping string above the jet pump, the through passage is made withthe possibility of installing in it, with the closure of the throughpassage, a device for delivering into and removing from the well thehousing with the jet pump, and in the bottom part of the housing of thejet pump a threaded hole is made for attaching autonomous measuringequipment to the housing, wherein the outer diameter (D) of the jet pumphousing is at least 1.0 mm less that the least inner diameter (D₁) ofthe piping string, the diameter (D₂) of the axial passage in the sealingassembly is at least 0.01 mm higher than the diameter (D₃) of the cable,and the diameter (D₄) of the passage for supplying the pumped out mediumis at least 2 mm higher than the diameter D₃ of the cable, and sealingrings and a retaining mechanism are installed on the housing of the jetpump.

[0008] The analysis of the operation of the well jet unit has shown thatthe its reliability may be increased through more optimal arrangement ofthe construction components in the jet unit housing and making themaccording to strictly defined dimensions. It has been found out, inparticular, that the diameter of the passage for supplying the pumpedout medium may not be taken arbitrarily. It is due to the fact that atoo large diameter of the passages results in a reduction in thestrength of the unit, but a too small diameter of those passages resultsin lowering the capacity of the jet pump. It has been found out in thisconnection that the making of the diameter of the passage for supplyingthe pumped out medium at least 2 mm higher than the diameter of thecable enables to pass to the jet pump the greatest amount of the mediumpumped out of the well, which corresponds to the maximum capacity of thejet pump, with the minimal hydraulic losses. As to the upper limit, itshould be defined by the strength characteristics of the jet pumpconstruction, and, first of all, by those of the jet pump housing. Ineach particular case this value is to be determined individually. In thecourse of the unit operation studies of different well modes areconducted. It is necessary to install and remove the housing with thejet pump in the piping string. It has been determined that it isadvisable to make the diameter of the jet pump housing at least 1.0 mmless than the inner diameter of the piping string, and sealing rings anda mechanism which retains the jet pump housing in its position relativeto the support in the well. In the result, possible sticking of thehousing in the piping string is precluded and the overflowing of themedium from the space above the housing to the under-packer space in thewell is ensured. It has already been said that in the process of theunit operation it is necessary to move instruments and equipmentinstalled on the cable along the well and, at the same time, minimizethe medium flow through the axial passage of the sealing assembly. Ithas been achieved by making the diameter of the axial passage in thesealing assembly at least 0.01 mm greater than the diameter of thecable, onto which the instruments and equipment are installed. Themaking of a threaded hole in the bottom part of the jet pump enables toinstall various measuring devices operating autonomously, and, owing tothis, expand the range of studies conducted in the well.

[0009] Thus, the objective of the invention—to optimize the arrangementand the dimensions of the construction components of the unit and, owingto it, raise the reliability of operation of the downhole jet unit—hasbeen achieved.

BRIEF DESCRIPTION OF DRAWINGS

[0010]FIG. 1 represents a longitudinal section of the disclosed well jetunit.

[0011]FIG. 2 represents a longitudinal section of the well jet unit withthe device for delivering into and removing from the well the housingwith the jet pump, which is installed instead of the sealing assembly.

PREFERRED EMBODIMENT OF THE INVENTION

[0012] The proposed well jet unit comprises a packer 1, a piping string2, having a support 3 wherein drain ports 4 are made and onto which ajet pump 6 with its housing 5 is installed, the said housing 5comprises: a passage 7 in communication with drain ports 4 for supplyingan active medium to the nozzle 8 of the jet pump 6 from the spacesurrounding the piping string 2, a passage 9 for supplying the mediumpumped out of the well to the jet pump 6 and a passage 10 for removing amedium mixture from the jet pump 6 into the inner cavity of the pipingstring 2 above the jet pump 6, and in the housing 5 above the passage 9for supplying the pumped out medium a through passage 11, being incommunication with the passage 9 and being made with a mounting face 12for installing a sealing assembly 13, and the sealing assembly 13comprises a through passage 14 with the possibility of leading, throughit and the passage 9 for supplying the pumped out medium, a cable 15 forthe purpose of installing on it, in the well below the jet pump 6,instruments and equipment with the possibility of moving them along thewell bore when the jet pump 6 is or is not operated. The through passage11 is made with the possibility of installing in it, with the closure ofthe through passage 11, a device 17 for delivering into and removingfrom the well the housing 5 with the jet pump 6, and in the bottom partof the housing 5 of the jet pump 6 a threaded hole 18 is made for thepurpose of connecting with the housing 5 of the autonomous measuringequipment 21, wherein the outer diameter (D) of the housing 5 of the jetpump 6 being at least 1.0 mm less than the least inner diameter (D₁) ofthe piping string 2, the diameter (D₂) of the axial passage 14 in thesealing assembly 13 is at least 0.01 mm greater than the diameter (D₃)of the cable 15, and the diameter (D₄) of the passage 9 for supplyingthe pumped out medium being at least 2 mm greater than the diameter (D₃)of the cable 15, the sealing rings 19 and the retaining mechanism 20being installed onto the housing 5 of the jet pump 6.

[0013] The piping string 2 with the packer 1 and the support 3 arelowered into the well, and the packer being installed above theproducing formation. Then the packer 1 is put into the operatingposition where it divides the well space surrounding the piping string2. Then the housing 5 with the jet pump 6 and the sealing assembly 13 aswell as the instruments and equipment arranged on the cable 15 below thehousing 6 are lowered into the well. The housing 5 with the jet pump 6are fixed in the support 3 by using the retaining mechanism 20. Theworking medium, e.g., water, salt solution, oil, etc., is pumped intothe hole clearance surrounding the piping string 2. From the holeclearance the working medium flows through the ports 4 and the passage 7into the active nozzle 8 of the jet pump 6. Within several seconds afterthe pumping of the working medium through the active nozzle 8 a stablejet is formed at its outlet, which, flowing out of the nozzle 8,entrains the medium surrounding it into the jet pump 6, which results ina pressure reduction, first, in the passage 9 for supplying the pumpedout medium and then in the under-packer space in the well, thus creatinga pressure drawdown onto the producing formation. The pressure reductionvalue depends on the speed at which the working medium comes through theactive nozzle 8, such speed depending, in its turn, on the pressure atwhich the pumped out medium is discharged into the hole clearance abovethe packer 1. In the result the formation medium comes along the pipingstring 2 and through the passage 9 into the jet pump 6 where it is mixedwith the working medium, and the mixture of the media flows by theenergy of the working medium along the piping string 2 from the well onthe surface. During pumping out the formation medium with the use of theequipment and instruments 16 installed on the cable 15 the parameters ofthe pumped out formation medium are monitored, and the producingformation is influenced by physical fields. According to a set task itis possible to move the instruments and equipment 16 along the well. Ifthe installation of the instruments and equipment 16 on the cable 15below the housing 5 of the jet pump 6 is not necessary, the device 17 isinstalled in the through passage 11 instead of the sealing assembly 13,and the device 17 is used for installing into and removing from thepiping string 2 the housing 5 with the jet pump 6 and the autonomousmeasuring equipment 21, if the latter has been installed on the housing5.

Industrial Applicability

[0014] This invention may be applied in testing, developing andoperating oil and gas condensate wells as well as during workover jobson them.

What is claimed is:
 1. A well jet unit which comprises a packer, apiping string having a support wherein drain ports are made and ontowhich a jet pump in its housing is installed, the said housing of thesaid pump comprising: a passage for supplying an active medium to thenozzle of the jet pump, a passage for supplying the medium pumped out ofthe well to the jet pump, and a passage for removing a media mixturefrom the jet pump, and in the housing, above the passage for supplying apumped out medium, a through passage in communication with the latterbeing made with a mounting face for installing a sealing assembly, andthe sealing assembly comprises a through passage with the possibility ofleading through it and the said passage for supplying the pumped outmedium a cable for the purpose of installing, in the well below the jetpump, instruments and equipment with the possibility of moving themalong the well bore when the jet pump is or is not operated,characterized in that, according to this invention, the passage forsupplying the active medium to the nozzle of the jet pump communicateswith the drain ports and, through the latter, with the space surroundingthe piping string, the passage for removing a media mixture from the jetpump communicates with the inner cavity of the piping string above thejet pump, the through passage is made with the possibility of installingin it, with the closure of the through passage, a device for deliveringinto and removing from the well the housing with the jet pump, and inthe bottom part of the housing of the jet pump a threaded hole is madefor attaching autonomous measuring equipment to the housing, wherein theouter diameter (D) of the jet pump housing is at least 1.0 mm less thatthe least inner diameter (D₁) of the piping string, the diameter (D₂) ofthe axial passage in the sealing assembly is at least 0.01 mm greaterthan the diameter (D₃) of the cable, and the diameter (D₄) of thepassage for supplying the pumped out medium is at least 2 mm greaterthan the diameter D₃ of the cable, and sealing rings and a retainingmechanism being installed on the housing of the jet pump.